Folding box construction



2,838,222 Paiented June 1Q, 1958 FGLDENG BGX CONSTRUCTIQN (Ionstantine .lohn Papadopoulos, Chicago, ill.

Application July 29, 1952, Serial No. 301,431

4 Claims. (Cl. 229-36) The present invention relates to improvements in folding or knockdown boxes, and more particularly to 1mprovements in knocked down boxes disclosed in my copending application, Serial No. 276,737, filed March 15, 1952, and now abandoned.

An object of this invention is to provide an improved one-piece knockdown box which can be economically manufactured and which can be readily and quickly assembled by the consumer.

Another object of this invention is to provide a onepiece knockdown box which has an improved interlocking tongue and slot construction for retaining the sides of the box in position, which construction permits the tongue to be readily inserted through the slot and securely retained in position.

Another object of-this invention is to provide an improved integral handle structurefor knockdown boxes of the above described type.

Other objects and advantages of the present invention will be apparent from the following description and the accompanying drawings, wherein:

Fig. l is a plan view, showing a novel flat blank from which containers involving the principles of this invention may be assembled;

Fig. 2 is a perspective view, showing the improved knockdown box of this invention at an intermediate stage of assembly;

Fig. 3 is a perspective view, showing a completed box embodying the features of this invention.

Referring now more specifically to the drawings, wherein like parts are designated by same numerals throughout the various figures, a knockdown box, involving the principles of this invention, may be constructed from the flat blank 10, shown in Fig. l. The blank is preferably constructed of heavy paper, cardboard, fibre, or any other suitable material.

The blank 10 includes a bottom panel 12, which is defined by bend lines 14, 16, 18, and 20, which bend lines are arranged in a substantially rectangular formation. If desired, the bend lines may be scored in the usual manner. A side panel 22 is articulated to the panel 12 along the bend line 14, and an opposed side panel 24 is articulated to the panel 12 along the bend line 18. In this embodiment, the outer free edges 26 and 28 of the side panels 22 and 24, respectively, are inclined outwardly from their ends toward their mid portions, as is clearly shown in Fig. 1. An end or looking flap 30 is articulated to one end of the side panel 22 along a bend or fold line 32, which line may be scored if desired. The end flap 30 is provided with a locking tongue 32, which extends inwardly from the inner edge 34 of the flap toward the center of the blank 10. At the junction of the tongue 32 with the inner edge 34, the flap 30 is provided with a short slit 36, which extends in the general direction of the tongue and which is for a purpose more fully described hereinbelow. I

A second end flap 38 is articulated to one end of the side panel 24 and is separated therefrom by a bend or fold line 40. The end fiap 38 is provided with a slit 42, which extends generally longitudinally of the blank 10 so that when the end flap is folded to the position shown in Fig. 2, the slit 42 is disposed generally parallel to the bottom panel 12. The slit 42 merges at its outer end with a relatively short slit 44, which short slit is directed inwardly toward the center of the carton or box blank so that when the flap 38 'is folded to the position shown in Fig. 2, the relatively short slit 44 extends trans verse of the bottom panel 12. At the opposite end of the side panel 24 from the end flap 38 is another end flap 46, which is joined to the side panel along the scored bend line 48. The end flap 46 is substantially identical to the above described end flap 30 and, therefore, need not be described in detail. An end flap 50, which is substantially identical to the above described flap 38, is articulated to the end of the side panel 22 along the bend or fold line 52, as shown in Fig. 1.

Side or end panels 54 and 56 are articulated to the opposite fold lines 16 and 20, respectively, which define the ends of the bottom panel 12. It should be noted that the side edges of the end panels 54 and 56 flare outwardly from their junctions with the bottom panel 12 so that the sides or ends of the assembled box will be wider at their tops than at their bottoms. In this connection, it should also be noted that the fold lines 32 and 52 and 40 and 48, which define the ends of the side panels22 and 24, respectively, are also flared outwardly from their inner or bottom ends.

Extending outwardly from the upper or outer edges 58 and 60 of the end or side panels 54 and 56 are top panels 62 and 64. The top panels 62 and 64 preferably are of such a length that when they are folded to a closed position, as shown in Figs. 2 and 3, they will complement each other to close the top of the container. A handle member 66 is articulated to the end of the top panel 62 along the fold or bend line 68; The handle member 66 is cut along the line 70 and preferably scored along the dot and dash line 72 to provide a tab 74 for a purpose to be more fully described below. A second handle member 76 is articulated to the end of the top panel 64 along the bend or fold line 78. The handle member 76 is provided with an elongated opening or slot 80 through which the hand of a person carrying the box may be inserted.

A pair of locking flaps 82 and 84 extend from the opposite edges of the top panel 62, which edges are defined by the scored bend lines 86 and 88. These locking flaps 82 and 84 are preferably substantially triangular in form, and they carry at their outer ends locking tongues 91) and 92, which extend outwardly from the edges 94 and 96, respectively. At the junction of the locking tongue and the edge 94, a relatively short slit 98 is formed in the locking flap S2, which'slit extends transversely of the tongue 90. A similar slit 1% is formed in the locking flap 84. A second pair of locking flaps 102 and 1414 having tongues 106 and 108 are joined to the opposite edges of the top panel 64 along the bend lines 116 and 112, respectively. The flaps 102 and 104 are identical to the flaps 82 and 84, and, therefore, need not be described in detail. It should be noted that the flaps 82, 84, 102 and 104 and their respective tongues are shorter than the width or height of the side panels 22 and 24. This structure allows the box to be made in many sizes and shapes since the material for extending the flaps 39, 38, 46 and 54 is available outside of the top panel locking flaps. 7

When assembling the box from the fiat blank 10 shown in Fig. .1, the end flaps 3t and 38 are first grasped and folded to positions extending substantially normallyto their respective side panels 22 and 24. Then by moving the end flaps 3t) and 38 toward the center of the blank and, hence, towards each other, the side panels 22 and 24 are folded to generally upstanding positions. During this movement, the end of the locking tongue 32 is in sorted through the slot 42 in the end flap 38. It should be noted that the end of the tongue 32 is rounded to facilitate this insertion. As the end flaps and the side panels are moved toward their finally assembled position shown in Fig. 2, the short slit 36 in the flap 30 is moved into interlocking relationship with the short slit 44 in the flap 38 so that the edges defining these slits engage one another to restrain relative movement of the two flaps laterally with respect to the bottom panel 12, thereby securely fastening the end fiaps together to support and hold relatively rigidly the side panels 22 and 24 in their upstanding positions. It is, of course, understood that the initial folding of the blank may be started with the end flaps 46 and 50 rather than the flaps and 38, as described. In any event, after the first pair of flaps has been assembled, as described above, the other pair of end flaps is then similarly assembled. One of the end panels, for example end panel 56, is then folded upwardly along the assembled end flaps 46 and 50, and the top panel 64 is folded downwardly until it engages the outer edges 26 and 28 of the side panels 22 and 24, respectively. During this downward folding of the top panel, the tongues 106 and 108 of the locking flaps are inserted through slits 114 and 116 formed in the side panels 22 and 24. It should be noted that the ends of the locking tongues are curved and that the slits 114 and 116 are also curved to facilitate this assembly. It should also be noted that the slits 114 and 116 are curved upwardly until their upper end portions become aligned with the above described relatively short slits formed at the junction of the locking tongues with the edge of the locking flaps so that these relatively short slits may be moved past the upper ends of the slits 114 and 116 to lock the tongues effectively in position and, thereby, securely retain the top panel in its closed position, as shown in Fig. 2. At this stage of assembly, the handle member 76 may be bent so that it extends outwardly, as shown in Fig. 2. The end panel 54 and the top panel 62 are then folded in the same manner as described above for the end panel 56 and the top panel 54. The locking tongues 90 and 92 are then inserted through the slits 118 and 120 in the side panels 22 and 24, which slits are identical to the above described slits 114 and 116. The tab 74 in the handle member 66 is then folded through the slit 80 in the handle member 76 and then upwardly, as shown in Fig. 3, whereby the tab effectively retains the two handle members together and also provides a smooth rounded edge 122 for engagement with the users hand.

As is clearly shown in the drawings, the upper ends 125, 127, 129 and 131 of slots 114, 116, 118 and 120 are located in straight lines extending diagonally between the center points 133 and 135 on the upper edges of the side panels 22 and 24 and the corners 137, 139, 141 and 143 of the bottom panel. In addition, it is seen that the points of engagement between the sides 22 and 24 and the locking tongues are at the upper ends of the slots. This structure is important particularly in combination with the fact that the junctions between the handles and the top panels extend to the outer of side edges of top panels since the box is provided with substantial resistance to tilting and will not come apart when supported by the handles. These advantages result from the fact that the efliect is substantially the same as if the handles were connected by diagonal members directly to the corners of the bottom panels for obtaining maximum stability and that the resultant of the force or weight components extends along the diagonals between the handles and the bottom corners to constantly urge the tongues into locking position with maximum effectiveness. Other advantages are that the weight of the box is supported equally by the tongues transferred uniformly to the handle members and there is substantially no torque applied to the tongues which might twist and tear them relatively easily but, on the contrary, the forces applied to the tongues extend along the diagonal lines.

From the above description, it is seen that the present invention provides a novel knockdown box structure which enables the box to be folded from a flat blank very quickly and easily since the first pair of cooperating end flaps having an interlocking tongue and groove may be assembled during the same movement which brings the sides of the box to their upstanding assembled position. This initial assembly is relatively and easily handled so that the subsequent steps of folding the ends and top panels may be readily formed. Furthermore, it is seen that the novel formation of the locking flaps and tongues extending from the top panels along with the slits in the side panels enables the tongues to be readily inserted through the slits while the top panels are being folded to their closed positions. In addition, it is seen that the novel formation of the tongues and the relatively short slits formed in the flaps adjacent the tongues provides a knockdown box which may be securely and relatively rigidly held together.

While the preferred embodiments of the present invention have been described and illustrated herein, it is obvious that the novel features of this invention may be applied to containers and boxes having various shapes and sizes, such as those illustrated in my above mentioned co-pending application. It is, therefore, clear that various changes may be made in the details of the dis closed structures without departing from the spirit and scope of the appended claims.

I claim:

1. A one-piece knockdown box, comprising a bottom panel, a pair of opposed side panels articulated to opposite edges of said bottom panel, a pair of end panels articulated to other opposite edges of said bottom panel, a pair of complementary top panels each articulated to an upper edge of one of said end panels and having inner edges disposed substantially over the middle of said bottom panel, a pair of juxtaposed upstanding handle members each articulated to the inner edge of one of said top panels, the junctions between said handles and top panels extending substantially the full width of said top panels, a pair of locking flaps articulated to side edges of each top panel and depending along said side panels, each of said locking flaps having a tongue portion disposed between inner and outer edges of its associated top panel,

and each of said side panels having a pair of slots therein for receiving said locking tongues, each of said slots having a terminal end engageable with one of said tongues and disposed at a point substantially in a diagonal line extending from a point at the middle of the upper edge of its associated side to a corner of the bottom panel, whereby to restrain tilting of the box when the box is supported by said handle members and to distribute the weight of the box substantially equally to the handles through all of said locking flaps, and a pair of end flaps articulated to each pair of adjacent ends of said side panels and extending inwardly along the inner surfaces of the adjacent end panels and each pair of end flaps having cooperating locking tongue and slit means for locking them together.

2. A one-piece knockdown box as defined in claim 1, wherein said tongue portions project toward the middle of the box so as to be drawn constantly into locking engagement with the sides when the box is supported by the handle member.

3. A one-piece knockdown box as defined in claim 1, wherein said handle members have aligned finger openings above the junctions between the handle members and the top panels.

4. A one-piece knockdown box as defined in claim 1, wherein said ends of the slots are located at least about 5 6 halfway up on the side panels and said locking flaps are 2,323,782 Kretchmer July 6, 1943 substantially shorter than the height of said side panels. 2,341,762 Conklin Feb. 15, 1944 2,355,729 Inman Aug. 15, 1944 References Cited in the file of this patent 2,4 7, 5 Biskamp Sept 17, 1946 UNITED STATES PATENTS 5 2,605,038 Wells y 29, 1952 2,041,021 Quagliotti May 19, 1936 FOREIGN PATENTS 2,074,638 l k M 1937 104,043 Sweden 17, 1942 

